The present invention relates to a bus connection structure for connecting a plurality of processers and I/O unit adapters belonging to these processors inside a single cabinet and, more particularly, to a bus connection structure allowing construction of a flexible interruption control system.
Conventionally, when a system consisting of a plurality of processing units connected to a common bus and a plurality of adapters connected to the processing units is built in a single cabinet, the processing units and the adapters are connected in accordance with a wiring pattern on a backboard manufactured according to a predetermined mounting format, or the backboard is subjected to wire connection depending on the system structure. When an interruption signal terminal arranged on the backboard is to be replaced upon updating of the system, a switch is used.
The conventional bus connection structure described above has a limited system application range and has no flexibility for system updating. In addition, the conventional structure includes a factor of the erroneous operation of the system due to a setting error of the switch. When the system is updated in the bus connection structure using the wiring pattern on the backboard according to the predetermined mounting format, the wiring pattern for bus connection is fixed. Therefore, no adapters can be added, or when an adapter unit is removed, an unnecessary connector remains. When a system is constructed by wiring the backboard, if the system is to be updated, wiring for a new system is time-consuming and costly. In addition, wiring errors may occur at different locations depending on individual systems.
When a switch is arranged, if an identical adapter is connected to one processor, switches of the adapters must be set differently when the interruption priority order is changed.